Distributor type fuel injection pump

Abstract

A distributor type fuel injection pump of the present invention is of the Lucas type having a rotor rotatably driven by an engine but not reciprocated. Spill ports of the same number as that of the cylinders of the engine communicating with a pump chamber are opened at an equal peripheral interval on the outer peripheral surface of the rotor, and a spill ring to cover the spill ports is slidably mounted on the outer peripheral surface of the rotor. A spill groove is formed to extend axially on the inner peripheral surface of this spill ring. One edge of the spill groove, which initially meets the respective spill ports during the pressurizing step for pressurizing the fuel in the pump chamber, is inclined to the axis, and the other edge of the spill groove is parallel to the axis.

What is claimed is: 
     
       1. A distributor type fuel injection pump for distributing fuel into combustion chambers of an internal combustion engine comprising: a rotor rotatably driven by the engine and having therein a fuel passage coaxial with the rotor axis and a pump chamber communicating with the fuel passage,   pumping means for pressurizing fuel in the pump chamber by the rotatable drive of the rotor to deliver the pressurized fuel through the fuel passage, the pumping means having a cam ring disposed coaxially to surround the rotor and formed with a cam surface on the inner peripheral surface thereof and plungers reciprocating radially of the rotor in cooperation with the cam ring, thereby introducing fuel to the pump chamber and pressurizing the fuel introduced into the pump chamber;   distributing means for distributing the pressurized fuel delivered from the pump chamber to the fuel passage by the pumping means toward the respective combustion chambers of the engine; and   adjusting means for adjusting the quantity of pressurized fuel to be distributed by spilling the pressurized fuel delivered from the pump chamber to the fuel passage, said adjusting means including control means which controls a spill start time at which the spill of the pressurized fuel contained in the fuel passage is started and which sets, before the introduction of the fuel is started, a spill finish time at which the spill of the pressurized fuel contained in the fuel passage is stopped.   
     
     
       2. The distributor type fuel injection pump according to claim 1, wherein the adjusting means comprises spill holes formed in the same number as the combustion chambers of the engine in the rotor, each of the spill holes communicating at one end independently with the fuel passage and opened at the other end to the outer peripheral surface of the rotor, the open other ends being arranged at equal circumferential intervals on the outer peripheral surface of the rotor; a spill ring liquid-tightly and slidably mounted on the outer peripheral surface of the rotor so as to cover the open other ends of the spill holes; and a spill groove formed to extend axially on the inner peripheral surface of the spill ring in such a manner that one edge of the spill groove, which initially meets the respective open other ends of the spill holes upon rotation of the rotor during the pressurization of the fuel, is inclined to the axis of the rotor, and the other edge of the spill groove is parallel to the axis of the rotor. 
     
     
       3. The distributor type fuel injection pump according to claim 1, wherein the adjusting means comprises a spill hole formed in the rotor, the spill hole communicating at one end thereof with the fuel passage with the other end opening to the outer peripheral surface of the rotor; a spill ring liquid-tightly and slidably mounted on the outer peripheral surface of the rotor so as to cover the opening end of the spill hole; and spill grooves arranged in the same number as the combustion chambers of the engine on the inner peripheral surface of the spill ring so as to extend axially at equal circumferential intervals in such a manner that one edge of the respective spill grooves, which initially meets the opening end of the spill hole upon rotation of the rotor during the pressurization of the fuel, is inclined to the axis of the rotor, and the other edge of the respective spill grooves is parallel to the axis of the rotor. 
     
     
       4. The distributor type fuel injection pump according to claim 1, wherein the adjusting means comprises a spill ring, which is slidably and liquid-tightly mounted on the outer peripheral surface of the rotor, the spill ring including a spill hole opening at one end to the inner peripheral surface of the spill ring, spill grooves arranged at equal circumferential intervals on the outer peripheral surface of the rotor covered by the spill ring in the same number as the combustion chambers of the engine, the spill grooves being formed to extend in the axial direction of the rotor in such a manner that one edge of the respective spill grooves, which initially meets the opening end of the spill hole upon rotation of the rotor during the pressurization of the fuel, is inclined to the axis of the rotor, and the other edge of the respective spill grooves is parallel to the axis of the rotor, and communicating holes formed in the rotor for communication independently between the spill grooves and the fuel passage.